By the beauty of colouring, the painters mean that disposition of colours on objects, together with their proper shades, which appear at the same time both distinctly varied and artfully united, in compositions of any kind; but, by way of pre-eminence, it is generally understood of flesh-colour, when no other composition is named.
To avoid confusion, and having already said enough of retiring shades, I shall now only describe the nature and effect of the prime tint of flesh; for the composition of this, when rightly understood, comprehends every thing that can be said of the colouring of all other objects whatever.
And herein (as has been shewn in [Chapter VIII], of the manner of composing pleasing forms) the whole process will depend upon the art of varying; i. e. upon an artful manner of varying every colour belonging to flesh, under the direction of the six fundamental principles there spoken of.
But before we proceed to shew in what manner these principles conduce to this design, we shall take a view of nature's curious ways of producing all sorts of complexions, which may help to further our conception of the principles of varying colours, so as to see why they cause the effect of beauty.
It is well known, the fair young girl, the brown old man, and the negro; nay, all mankind, have the same appearance, and are alike disagreeable to the eye, when the upper skin is taken away: now to conceal so disagreeable an object, and to produce that variety of complexions seen in the world, nature hath contrived a transparent skin, called the cuticula, with a lining to it of a very extraordinary kind, called the cutis; both which are so thin any little scald will make them blister and peel off. These adhering skins are more or less transparent in some parts of the body than in others, and likewise different in different persons. The cuticula alone is like gold-beaters-skin, a little wet, but somewhat thinner, especially in fair young people, which would shew the fat, lean, and all the blood-vessels, just as they lie under it, as through Isinglass, were it not for its lining the cutis, which is so curiously constructed, as to exhibit those things beneath it which are necessary to life and motion, in pleasing arrangements and dispositions of beauty.
The cutis is composed of tender threads like network, fill'd with different colour'd juices. The white juice serves to make the very fair complexion;—yellow, makes the brunnet;—brownish yellow, the ruddy brown;—green yellow, the olive;—dark brown, the mulatto;—black, the negro;—These different colour'd juices, together with the different meshes of the network, and the size of its threads in this or that part, causes the variety of complexions.
A description of this manner of its shewing the rosy colour of the cheek, and, in like manner, the bluish tints about the temple, &c. see in the profile [fig. 95 T p. II], where you are to suppose the black strokes of the print to be the white threads of the network, and where the strokes are thickest, and the part blackest, you are to suppose the flesh would be whitest; so that the lighter part of it stands for the vermilion-colour of the cheek, gradating every way.
